1. Field of the Invention
The present invention relates to a digital broadcasting reception system for receiving a digital broadcasting signal and storing and searching the same, and more particularly, to an apparatus for storing and searching audio/video data containing additional information in which a user stores audio/video data of a desired program together with the additional information corresponding to the program, resulting in easy and quick search.
2. Description of the Related Art
According to quick spread of digital media and development of a digital signal processing technology, a digital broadcasting service using a ground wave or a satellite are widely being spread. A general digital broadcasting service is realized on the basis of the MPEG (Moving Picture Experts Group) standard. To perform a digital broadcasting service according to the MPEG standard, program specific information (PSI) such as audio/video information and program information which are compressed with respect to each broadcasting channel is transmitted in the form of a packet of a transport stream (TS). The MPEG TS packet is composed of 188 bytes, among which 4 bytes are header information, and 184 bytes are payload information. The 4-byte header information includes packet identifier (PID) representing what each packet is. Also, the PSI packet transmitted in the form of a TS packet has at least two tables. That is, one is a program map table (PMT) for identifying TS packets of basic streams such as a video stream, an audio stream or a data stream for each program constituting multiplexed programs and the other table is a program association table (PAT) for identifying the PMT. The PAT includes the PID such as a network information table (NIT), a service description table (SDT), a time data table (TDT) and the PMT. The NIT includes the PID such as an event information table (EIT). The SDT includes information with respect to a provider such as broadcasting station information, and the TDT includes information with respect to an absolute time of a broadcast program. The EIT includes information on an electronic program guide (EPG). The EPG information is information with respect to each program such as an edit time, a title, a content and a program classification of a corresponding program. Also, the PMT includes the PID with respect to an audio/video packet of a corresponding program. The audio/video packet exists in the form of a packetized elementary stream (PES) generally, including a bitstream in which audio and video have been compressed. The header portion of the PES includes a clearance space in which user's private data can be inserted. In particular, a user data region is defined in a video bitstream, providing a syntax for allowing user desired information to be inserted thereinto.
In a digital broadcasting service transmitted in the form of a TS packet, a packet including audio/video data of a corresponding program and all TS packets including a PSI packet should be stored in the form of a single program TS packet, in order to store particular audio/video data contained in a particular packet. Also, in order to search the stored audio/video data, a process for decoding a single program TS packet should be performed, which will be described in more detail with reference to FIGS. 1 and 2.
FIG. 1A is a block diagram showing a general storage device for storing audio/video data. FIG. 1B shows a pattern of a single program TS packet.
In FIG. 1A, a TS decoder 11 receives a TS packet and classifies the received TS packet into various PSI packets such as a PAT, PMT, NIT and EIT. The classified PSI packet is stored in a storage medium 16 under the control of a controller 15. Also, the TS decoder 11 extracts a corresponding audio/video packet from the input TS packet, using PID information of the audio/video packet with respect to a user desired particular program. The extracted audio/video packet is supplied to an audio/video packet processor 12. If the audio/video packet has been encrypted, the audio/video packet processor 12 decrypts the supplied audio/video packet using a decryptor 13, so as to be stored in a storage medium 16. The controller 15 reads the PSI packet stored in the storage medium 16 and a user selected audio/video packet so as to be output to a single program TS producer 14. The single program TS producer 14 produces a single program TS packet as shown in FIG. 1B, using the audio/video packet of the user selected program and the PSI packet, which are input via the controller 15, and stores the same in the storage medium 16 again. Referring to FIG. 1B, the single program TS packet includes all packets necessary for watching a user desired program. That is, the single program TS packet includes all PSI packets such as PAT, PMT, NIT, SDT, TDT and EIT packets necessary for a corresponding audio/video packet as well as an audio packet and a video packet.
FIG. 2 shows a general searching apparatus for searching audio/video data in which a stored single program TS packet is searched to allow a user to watch his or her desired program.
In FIG. 2, a PAT parser 111 in a single program TS decoder 110 receives a single program TS packet and searches a PAT packet. The PAT parser 111 detects PID information representing position of a PSI packet such as a PMT, SDT, TDT and NIT, and outputs each packet to each parser 112, 113, 114 or 115. The PMT parser 112 parses the PID information of the PMT packet input from the PAT parser 111 and outputs an audio/video packet to an audio/video decoder 17. Meanwhile, the NIT parser 113 extracts PID information of the EIT packet from the NIT packet and outputs the EIT packet to an EIT parser 116. The EIT parser 116, the SDT parser 114, and the TDT parser 115 read data of each packet according to the PID information of the parsed packet and outputs the read data to a search information comparator 18. The search information comparator 18 compares data of each packet supplied from each parser 114, 115 or 116 with user input search information. Here, the search information includes a title, a content and a time of a user desired program. The search information comparator 18 outputs the comparison result to an audio/video decoder 17, in the case that data of each packet is coincident with user desired search information. Then, the audio/video decoder 17 decodes a currently input audio/video packet and outputs the decoded result.
However, the above prior art requires a storage medium of a large capacity, since a PSI packet should be also stored in addition to an audio/video packet including audio/video data. Also, since data of the PSI packet stored together with the audio/video packet should be parsed in order to allow a user to search the stored audio/video packet and to watch a user desired program, a long searching time is consumed.